The invention relates to an arrangement for synchronizing or regulating the synchronism of printing presses and additional components. Furthermore, the invention relates to a method for synchronizing printing presses and additional components.
The main drive components of printing presses and additional components of printing presses are usually operated with direct current motors (DC drives) or alternating current motors (AC drives). It is essential here that the synchronism is ensured of the printing presses and the additional components, such as printing unit or units, folding unit or units, web guide or guides, etc.
In printing presses having DC drives, the synchronism is usually achieved internally by mechanical synchronization. In order to produce this mechanical synchronization, diverse line shafts and stationary shafts are used which couple the printing-press components to one another. A plurality of printing-press systems are likewise coupled to one another mechanically. It is disadvantageous here that the mechanical coupling also leads to undesirable transmission of mechanical vibrations.
In order to increase the printing volume or the product diversity, it is the desire of many users in the field of the printing industry to expand the functional scope of the printing presses or to connect a plurality of printing presses to one another. As a result, for example, the following requirements are made of the manufacturers of printing presses.
Printing presses which already exist are to be supplemented by components, such as additional printing units, additional folding units, etc. Printing presses which already exist are to be connected to further printing presses or are to be coupled to the latter. Printing presses which already exist and are based on DC drive technology are to be supplemented by components or by printing presses which are based on AC drive technology, that is to say printing presses and/or additional components with different drive types are to be connected to one another.
At present, the expansion of printing presses is solved as follows: if a printing press is expanded by one or more additional components, the components which are to be added are coupled to the line shaft mechanically or physically. If large distances are to be bridged here, for example through a dryer system, the coupling is expensive. The problem of vibration coupling (feedback) of mechanical vibrations remains in the mechanical connection of the printing press and additional component or components.
If two or more printing presses are to be connected to one another, these have previously also been coupled mechanically via one or more shafts. Here, the associated transmission of vibrations in the connected unit of printing presses is the greatest problem. These vibrations can have a negative effect on the print quality. They are produced by the spring properties of the shaft connection and of the driven mass moments of inertia. The mechanical coupling can be made more difficult by differences of the line shafts with respect to rotational direction and height. In general, these conditions require a complicated and expensive mechanical adaptation.
If a printing press which already exists is to be supplemented by one or more components, the printing press and the components being based on different drive technologies, use is made of the method of coupling which is known by the name “real line shaft”.
In the real line shaft, the coupling is realized via what is known as master/slave regulation. In this master/slave regulation, a sensor makes a setpoint signal available for the components which are to be added which have AC drive technology. Here, the old system part is the master and the new system part is the slave. The sensor detects the actual state of the system and the new system part is regulated according to this. The problems with this type of coupling are sufficiently known. A connection is set up which is similar to the mechanical coupling, as it were. The vibrations of the existing system are transmitted directly into the new system part. An external excitation of vibrations occurs, the effect of which reduces the print quality as seriously as stability problems when regulating which prevents operation.
The inventors have therefore set the object of making an arrangement and a method available, with which printing presses can be expanded inexpensively both with additional components and also with further printing presses and can be synchronized together, and the abovementioned problems of undesirable vibration coupling (feedback) are avoided in the process.
The inventors have discovered that, in printing presses having AC drives, the synchronism is achieved by what is known as a virtual line shaft, also called an electronic shaft. Here, the synchronism of the printing-press components is usually achieved electronically or partly also mechanically. The advantage of the electronic synchronization by means of a virtual line shaft/electronic shaft is that there is no direct mechanical feedback. An important feature of the virtual line shaft is that it makes the electronically generated setpoint values available. It synchronizes the drives. The basic principle of the virtual line shaft is based on the fact that every drive takes its setpoint values from this line shaft and is regulated according to this. This circumstance contributes substantially to improving the behaviour of printing presses and makes performance increases possible with a print quality which remains the same or is improved.
Furthermore, the inventors have discovered that the printing presses and expansion components can be decoupled in terms of vibrations with the aid of special synchronism regulation. The existing printing presses are equipped with an additional synchronism regulator. All synchronism regulators and the additional synchronism regulator are connected to one another. The virtual line shaft is formed in one of the synchronism regulators, depending on which system part is to assume the guidance function. All synchronism regulators operate with these generated setpoint values. Every system or component therefore operates for itself. Direct feedback, for example of vibrations, with the existing problems is therefore obviated.
This inventive concept can be used for the expansion with additional components in existing printing presses. The existing printing press and the additional component or components are equipped with an additional synchronism regulator for the expansion. The coupling takes place via the synchronism regulator, as has already been described.
Moreover, this method of coupling is also suitable in the expansion of printing presses with printing presses. The existing printing press is equipped with an additional synchronism regulator. The old and new components are connected with a virtual line shaft. The latter can be produced in different ways. Firstly, the virtual line shaft of the existing system can be transmitted by means of sensor emulation. In sensor emulation, the signal of a sensor is simulated electronically. This signal corresponds to the setpoint value of the system and is therefore available without mechanical coupling. The expenditure on change in the concept of the present solution is very low. The second method would be to connect the virtual line shaft directly. However, this requires the (synchronism) systems which are used to be compatible with one another.
Proceeding from the findings attained, the inventors provide an arrangement for synchronizing printing presses, to the extent that, for the synchronization of the units which are to be connected, at least one additional synchronism regulator is arranged on at least one unit and all synchronism regulators of the units are connected to one another.
As a result, a plurality of advantages are attained. For instance, the existing drive technology of the printing press, such as the motor and current regulation, can be retained. Moreover, mechanical decoupling and therefore an improved running property of the printing press are achieved. The invention provides simple coupling of existing printing-press systems, above all with DC drive technology. Furthermore, improved coupling is made possible for printing-press systems with AC drive technology. Costs can also be saved as a result of the inventive concept, as complicated mechanics, such as line shafts, are not necessary in the case of the printing presses being connected to printing presses or additional components. Advantages also result, however, with regard to safety requirements. The safety requirements can be implemented more cheaply as a result of the invention. In particular, the printing press or the printing-press system can be divided into separated risk regions.
It is advantageous if the additional synchronism regulator is arranged on the units which have DC drive technology.
In addition to the use of an additional synchronism regulator in the units which have DC drive technology, both the original unit and the unit which is to be connected can have in each case an additional synchronism regulator.
It is advantageous if at least one synchronism regulator forms a line shaft, the line shaft stipulating setpoint values for the other synchronism regulators. As a result, master/slave regulation of the connected units can be built up, in a similar manner to master/slave regulation with a real or physical line shaft, but the problems which occur there, such as regulation lag, are avoided.
In one particular embodiment, the synchronism regulator can have sensor emulation which simulates a signal of the sensor electronically. In this way, drive systems can be coupled which, for example, have only a corresponding sensor interface.
Furthermore, it is favorable if the synchronism regulator is integrated in the drive regulator. This embodiment is an inexpensive alternative.
Components of a printing press which have at least one AC and/or DC drive can be used as additional components. For example, the additional component can comprise at least one printing unit and/or one folding unit. Furthermore, the additional component can comprise at least one cooling unit and/or one web guiding unit.
In accordance with the arrangement, the inventors also provide a method for synchronizing printing presses and additional components, in which method a printing press and/or an additional component form/forms a unit and are/is connected to further units, and the drives of the connected units are synchronized, the units having either AC drives and/or DC drives and being synchronized internally via synchronism regulators in the case of an AC drive and via at least one drive shaft in the case of a DC drive. According to the invention, this method is improved to the extent that, for the synchronization of the units which are to be connected, electronic setpoint values are generated on at least one unit having at least one sensor, which setpoint values are fed to at least one additional synchronism regulator, and all synchronism regulators of the units are connected to one another and are adapted to these setpoint values.
Here, actual values can be detected by the sensor, for example the machine speed, which then generates corresponding setpoint values.
In the method, it is advantageous that, for synchronizing at least one synchronism regulator, a signal of a sensor is simulated electronically.
Furthermore, in the novel method, setpoint values for the other synchronism regulators are stipulated by at least one synchronism regulator, or sensor signals are simulated for other drive regulators.